The present invention relates to the discovery, identification, and characterization of novel human polynucleotides encoding proteins that share sequence similarity with human calcium dependent proteases. The invention encompasses the described polynucleotides, host cell expression systems, the encoded proteins, fusion proteins, polypeptides and peptides, antibodies to the encoded proteins and peptides, and genetically engineered animals that either lack or over express the disclosed genes, antagonists and agonists of the proteins, and other compounds that modulate the expression or activity of the proteins encoded by the disclosed genes that can be used for diagnosis, drug screening, clinical trial monitoring and the treatment of physiological disorders.
Proteases are enzymes that mediate the proteolytic cleavage of polypeptide sequences. In particular, calcium-dependent proteases such as calpains, have been found in virtually every vertebrate cell that has been examined for their presence. The calpain system has at least three well-characterized protein members that are activated in response to changes in calcium concentration. These proteins include at least two calpains that are activated at different concentrations of calcium, and a calpastatin that specifically inhibits the two calpains. Various tissue/species specific cDNAs have been described that are homologous to the calpains. Given the near ubiquitous expression of calpains, they have been implicated in a wide variety of cellular functions including, but not limited to, cell proliferation and differentiation, signal transduction, processes involving interactions between the cell membrane and cytoskeleton, secretion, platelet aggregation, cytokinesis, and disease. Accordingly, calpains represent a key target for the regulation of a variety of biological pathways.
The present invention relates to the discovery, identification, and characterization of nucleotides that encode novel human proteins, and the corresponding amino acid sequences of these proteins. The novel human proteins (NHPs) described for the first time herein share structural similarity with animal calcium-activated proteases, or calpains. As such, the novel genes represent a new class of protease proteins with a range of homologues and orthologs that transcend phyla and a broad range of species.
The novel human nucleic acid sequences described herein, encode proteins/open reading frames (ORFs) of 739, 723, 702, and 686 amino acids in length (see SEQ ID NOS: 2, 4, 6, and 8 respectively).
The invention also encompasses agonists and antagonists of the described NHPs, including small molecules, large molecules, mutant NHPs, or portions thereof that compete with native NHP, peptides, and antibodies, as well as nucleotide sequences that can be used to inhibit the expression of the described NHPs (e.g., antisense and ribozyme molecules, and gene or regulatory sequence replacement constructs) or to enhance the expression of the described NHP genes (e.g., expression constructs that place the described gene under the control of a strong promoter system), and transgenic animals that express a NHP transgene, or xe2x80x9cknock-outsxe2x80x9d (which can be conditional) that do not express a functional NHP.
Further, the present invention also relates to processes of identifying compounds that modulate, i.e., act as agonists or antagonists, of NHP expression and/or NHP product activity that utilize purified preparations of the described NHPs and/or NHP product, or cells expressing the same. Such compounds can be used as therapeutic agents for the treatment of any of a wide variety of symptoms associated with biological disorders or imbalances.
The Sequence Listing provides the sequences of 4 calpain-like ORFs that encode the described NHP amino acid sequences.